Occurrence of polycyclic musks in pore water of the sediment-freshwater system: passive sampler application

Polycyclic musks are aroma compounds used worldwide as substitutes for natural musks, which have become ubiquitous pollutants in the environment. The land-based input and partition behavior of musks in sediments and fresh water are important for understanding their fate in the aquatic environment. In this study, a 10 sediment samples were collected and used to determine three polycyclic musks: tonalide, galaxolide and cashmeran. All three pollutants were detected in the sediment of the Danube River, but in very low concentrations (< 2 ng/L). In the article, the ex-sity passive methodology of sediment sampling was applied. For this purpose, silicone rubber sheets were used so that, after establishing equilibrium relations between sediment and polymer, the concentration of musk could be determined. Relations of two important parameters for risk assessment- freely dissolved concentration (Cw) in the pore water and the accessible (releasable) concentration in the sediment (CAOC) were deviated the most in the Belegiš locality, with total Cw values of 0.003 ng/L for Galaxolide and Tonalide, and 0.02 ng/L for Cashmeran. The highly significant linear isotherms for musks obtained by the method of equilibrium passive sampling confirmed the partition driven nature of their exchange between water and sediment for the investigated sediments

Winter and Summer PM2.5 Land Use Regression Models for the City of Novi Sad, Serbia

In this study, we describe the development of seasonal winter and summer (heating and non-heating season) land use regression (LUR) models for PM2.5 mass concentration for the city of Novi Sad, Serbia. The PM2.5 data were obtained through an extensive seasonal measurement campaign conducted at 21 locations in urban, urban/industrial, industrial and background areas in the period from February 2020–July 2021. At each location, PM2.5 samples were collected on quartz fibre filters for 10 days per season using a reference gravimetric pump. The developed heating season model had two predictors, the first can be associated with domestic heating over a larger area and the second with local traffic. These predictors contributed to the adjusted R2 of 0.33 and 0.55, respectively. The developed non-heating season model had one predictor which can be associated with local traffic, which contributed to the adjusted R2 of 0.40. Leave-one-out cross-validation determined RMSE/mean absolute error for the heating and non-heating season model were 4.04/4.80 μg/m3 and 2.80/3.17 μg/m3, respectively. For purposes of completeness, developed LUR models were also compared to a simple linear model which utilizes satellite aerosol optical depth data for PM2.5 estimation, and showed superior performance. The developed LUR models can help with quantification of differences between seasonal levels of air pollution, and, consequently, air pollution exposure and association between seasonal long-term exposure and possible health risk implications

Primer kombinovanja raspodele atmosferskih aerosola po veličinama dobijenih metodom merenja električne pokretljivosti i optičkom metodom

Atmosferski aerosoli u urbanim sredinama se sastoje od čestica različitih dijametara, koje mogu imati veličinu od par nanometara do par mikrometara. Stoga je za merenje koncentracije aerosola često neophodno koristiti više instrumenata, sa principijelno različitim metodama merenja. U ovom radu su korišćene metode zasnovane na merenju električne pokretljivosti čestica, za opseg dijametara od 10nm do 420nm, i merenju ekvivalentnog optičkog dijametra, za opseg dijametara od 300nm do 10um. Kao glavni rezultat, prikazani su primeri kombinovanja spektara veličina čestica koji su dobijeni pomoću ove dve komplementarne metode merenja. U procesu kombinovanja spektara veličina čestica moguće je modifikovati raspodelu dobijenu optičkim merenjima traženjem optimalne vrednosti indeksa prelamanja čestica tako da se dobije što bolje slaganje sa raspodelom dobijenom merenjem električne pokretljivosti. Kao ulazni podaci su korišćeni rezultati merenja iz kampanje mobilnog monitoringa u Novom Sadu 2022

Diurnal, Temporal and Spatial Variations of Main Air Pollutants Before and during Emergency Lockdown in the City of Novi Sad (Serbia)

Changes in air pollution in the region of the city of Novi Sad due to the COVID-19 induced state of emergency were evaluated while using data from permanently operating air quality monitoring stations belonging to the national, regional, and local networks, as well as ad hoc deployed low-cost particulate matter (PM) sensors. The low-cost sensors were collocated with reference gravimetric pumps. The starting idea for this research was to determine if and to what extent a massive change of anthropogenic activities introduced by lockdown could be observed in main air pollutants levels. An analysis of the data showed that fine and coarse particulate matter, as well as SO2 levels, did not change noticeably, compared to the pre-lockdown period. Isolated larger peaks in PM pollution were traced back to the Aralkum Desert episode. The reduced movement of vehicles and reduced industrial and construction activities during the lockdown in Novi Sad led to a reduction and a more uniform profile of the PM2.5 levels during the period between morning and afternoon air pollution peak, approximately during typical working hours. Daily profiles of NO2, NO, and NOX during the state of emergency proved lower levels during most hours of the day, due to restrictions on vehicular movement. CO during the state of the emergency mainly exhibited a lower level during night. Pollutants having transportation-dominated source profiles exhibited a decrease in level, while pollutants with domestic heating source profiles mostly exhibited a constant level. Considering local sources in Novi Sad, slight to moderate air quality improvement was observed after the lockdown as compared with days before. Furthermore, PM low-cost sensors’ usefulness in air quality assessment was confirmed, as they increase spatial resolution, but it is necessary to calibrate them at the deployment location